Process of treating waste sulfite liquors, &amp;c.



STATES AENT BEIG VIGGO DREWSEN, 0F BROOKLYN, NEW YORK. ASSIGNOR T0 WEST VIRGINIA PULP & .PAIER COMPANY, OF NEW YORK. N. Y., A CORPORATION OF DELAWARE.

PROCESS OF TREATING WASTE SULFITE LIQUORS, &c.

No Drawing.

7 '0 all whom it may concern:

Be it known that I, Vrooo DREwsnN, a citizen of the United States, and resident of the borough of Brooklyn. county of Kings, city and State of-New York, have made a certain new and useful Invention Relating to Processes of Treating Waste, Sulfite Liquors, &c., of which the following is a specification. y

This invention relates especially to the treatment of waste sulfite liquors, such as are produced in wood pulp paper manufacture by which the organic compounds therein may be converted by treatment with caustic alkali or the like, such as soda, lime or carbonate of soda. the mixture being preferably heated under pressure for several hours and then filtered to remove the precipitated lignin compounds, the filtrate apparently containing the converted lactonic acids and the like. This filtrate may then be concentrated and heated underpressure. if desired, with caustic soda or the like to the extent of twenty to fifty per cent. or so and then subjected to distillation with super heated steam which separates the acetone or other ketones and alcohols. etc.. this distillation taking place preferably after the cansticized mixture has been reduced to a sub stantiallv dry conditionby evaporation or admixture of large quantities of caustic lime or the like. The distillation residue may also be burned and leached to recover the soluble alkali material therein and the precipitated lignin compounds may also be further treated for conversion into tanning material, etc.

The waste sulfite liquor from paper digesters, etc., mav be neutralized with suitable caustic alkali. such'as soda. lime. etc., which is preferably used in considerable excess and this action which seems to convert the organic compounds is promoted by heating and a itation. It is in many cases desirable to take the waste sultite liquor while still hot from the digester and run it into a suitable converter or digester containing an excess of caustic alkali. such as two to six per cent. or so of caustic soda, caustic lime. etc.. which is allowed to react with the liquor at high temperatures for several hours. heat being supplied so as to keep the pressure up to 80 or 100 pounds more or less per square inch while the mixture is preferably agitated as by the use of suitable stirrers Specification of Letters Patent.

Patented Mar. 25, 1919.

in the digester, or by using a rotary digester or converter to effect this agitation. Such caustic alkali treatment seems to convert the organic compounds inthe sulfite liquor, the woody material being apparently converted into ligninor similar Compounds which tend to precipitate; and certain other organic components such as some of the sugars are apparently transformed into various lactonic acids or allied soluble compounds capable of being broken up or producing on dry distillation with steam under proper conditions. acetone or other ketones and alcohols. which may be used as solvents for pyroxylin or for the ordinary varnish gums and resins. The sulfurous acid previously combined with the woody material combines with the lime or other earthy alkali used for this conversion, so that it may be precipitated and recovered and used for the original digesting action on the wood or other fibrous material. It is furthermore possible since even the soluble inorganic compounds can be subsequently recovered in this process to use instead of calcium bisultite. sodium sulfite or other normal sulfite compounds for the original digesting action on the wood. etc.. and secure additional advantages in this way.

The con erted mixture is preferabl v separated bv filtration which may be more conveniently effected in some cases after carbondioxid gas has been percolated throu h the mixture preferablv at considerable pressure which tends to romote the precipitation and aggre ation of the particles of the lignin material. The lignin when separated b" fi tration from tle converted mixture usually represents some 30 per cent. or so of the drv wei ht of the organic matter in the original sulfite liquor and this lignin material mav of course be used for the manufacture of tanning material and may also be dried to form a finely divided organic compound suitable for u e for many purposes, such as for an inert filler in paint, linoleum and other products.

The filtrate se ured from the original sulfite digester liquor after su h conversion, or the sulfite liquor waste after the production of rain alcohol from the sulfite liquor by varlous processes after first subjecting it to aesimilar high temperature conversion with .ustio alkali. may be concentrated to -a 65 be finally burned in the in suitable multiple effect evaporators and then may be subjected to a further caustic alkali conversion by heating it with a large proportion of caustic soda or the like at ordinary, or preferably high pressures which seems to efl'ect a further conversion 'or splitting up of the organic compounds, possibly into simpler lactonic acids or allied compounds. Caustic soda to the extent of 1.0 to 50 per cent. or so of the concentrated solution may be used for this alkali converting action and the causticized mixture may then be submitted to distillation with superheated steam or the like in any desired way either by feeding the causticized mixture into a suitable retort with or without a preliminary drying out or evaporation of the mixture. Or if desired the causticized mixture may be made substantially dry or non-fluent by the incorporation of powdered unslakecl lime therewith sufii ient to combine with the water present and drive off considerable quantities of the water by the heat of slaking so as to convert the causticized material'into a dry powder. if desired, when about an equal weight of the quicklime has been used. It is of course understood that where a considerable excess of soda, etc., is originally in orporated with the waste sulfite liquor bevond that necessary to neutralize its. acid components, this excess of soluble soda or the like would be present with the filtrate containing the material subsequentlv o centrated and transformed for the drv distillation treatment so that in some cases it would be unnecessary to incorporate a ditional amounts of soda, etc., to effect this onversion in the manner described.

On distillation of the converted or caus- 4 ticized soluble material with superheated steam, for example, at 300 to 500 degrees C. or so acetone and other ketones and alcohols are produced to the extent of some 7 or 8 per cent. of the drv weight of the organic matter in the original sulfite liquor and several per cent. more 'of heavier oilv distillate is also secured besides considerable pro- 7 portions of other more volatile ,material, so e of W "1"ll is of a gaseous nature and which is suflkiently inflammable so as to be used for retort heating andother heating purposes if desired. The produ ts of distillation mav be separated or fractionated in env sui able wav to separate the more valu- 5 able volatile solvent from the other mate- -rial wh h includes several per cent. of a black oilv material substantiallv immis ible WJtlI water and of rather lighter-specific grav ty. A repeated dist llation may be resorted to in a column still for example, or

such an, apnaratus may be used to separate the original products of distillation.

The distillation residue in the retort may he'sub itted to still higher heat and may presence of air and nasaave nection with a number of illustrative mas terials, proportions, arrangements and orders of steps, to the details of which disclosure the invention is not of course to be limited, since what is claimed as new and what is desired to be secured by Letters Patent is set forth in the appended claims:

'1. The process of treating waste sulfite liquors which consists in incorporating there- -with an excess of caustic alkali. material and simultaneously agitating the mixture while heated for several. hours under about 100 pounds pressure, thereby precipitating the lignin compounds which are produced in fi1- tering oi? the liquid containing converted lactonie acids and related components in solution, in concentrating such filtrate andheating the same underv pressure with 20.

to 50 per cent. of caustic soda, in drying and subjecting the causticized mixture to distil lation with superheated'steam at about 300 to 500 degrees centigradeto roduce acetone or other ketones and alcohols and additional volatile material, in burning the distillation residue and recovering by leaching the soluble mineral matter therefrom. w r

2'. The process of treating waste 'sulfite liquors which consists in incorporating therewith an excess of caustic alkali material and simultaneously agitating the -mixture while heated for'several hours under pres- ;sure, in percolating carbon-dioxid through the material and precipitating the lignin compounds thus produced and filtering 0d the liquid containing converted lactonic' acids and related components in solution, in concentrating such filtrate and heating the same under pressure with 20 to 50 per cent. of caustic soda and in subjecting the causticized mixture to distillation with steam at about.300 to 500 degrees 'oentrigrade to produce acetone or other ketones and alcohols and additional volatile material.

" 3. lhe rocess of treating waste sulfite- I liquors which consists in incorporating therewith caustic alkali, material and simultaneously agitating the mixture while heated for several hours under pressure, in precipitating the lignin compounds thus produced and separating the liquid containing I converted lactonic acids or related components 'in solution, in concentrating such llquid and heatingthe' same with a large proportion of caustic soda, and in subjecting.

the causticized mixture to distillation with steam to produce acetone or other ketones and alcohols and additional volatile material.

4. The process of treating waste sulfite liquors which consists in incorporating therewith an excess of caustic soda and simultaneously heating and agitating the mixture for several hours under about 10 0 pounds pressure, in percolating carbondioxid through the material and precipitating the lignin compounds thus produced and filtering oil the liquid containing converted material in solution, in concentrating such filtrate and heating the same with 20 to 50 per cent. of alkali caustic and in dry ing and subjecting the converted material to distillation with superheated steam at about 300 to 500 degreescentigrade to produce acetone or .otherketones and additional volatile material.

5. The rocess of treating waste sulfite liquors which consists in incorporating therewith an excess of caustic soda and simultaneously heating the mixture for secoral hours under pressure, in precipitating the .lignin compounds thus produced and filtering off the liquid containing lactonic acids or otherconverted material in solution, in concentrating such filtrate and heating the same with caustic alkali and in dry:

ing and subjecting the converted material to distillation with steam atabout 300 to. 500

degrees other ketones and additional volatile macentigrade to produce acetone or terial.

6. The process therewith an excess of caustic soda and simultaneously heating the mixture for sevof treating waste sulfiteliquors which consists in incorporatingeral hours under pressure, in precipitating the lignin compounds thus produced and separating the liquid containing lactonic acids or other converted material in solution, and in drying and subjecting the converted material to distillation with steam to produce acetone or other ketones and additional, volatile material.

.or other ketone or alcohol.

8. The process of treating waste sulfite liquor material which consists in treating the material with an excess of caustic soda and heating the same until conversion producing'lactonic or similar converted soluble material takes place and in distilling the converted material with steam to produce acetone or other ketone or alcohol.

9. The process of treating waste sulfite liquor material which consists in heating the same in the presence of caustic soda until conversion takes place and in distilling the converted material at about 800 to 500 degrees centigrade to produce acetone or other ketone or alcohol.

VIGGO DRElVS EN.

Witnesses:

HARRY L. DUNCAN, JEssIE B. KAY. 

